Disentangling the effects of predation and oceanographic fluctuations in the mortality of two allopatric seabird populations

摘要: Life-history traits of migratory seabirds are influenced by changing conditions at breeding and wintering grounds. Climatic predation known to impact populations’ survival rates, but few studies examine their effect simultaneously. We used multievent capture–recapture models assess mortality due environmental in European storm petrels (Hydrobates pelagicus) two allopatric colonies (Mediterranean Atlantic). Predatory the showed annual variation, being around 0.05 certain years. Mortality sea differed between oceanic basins, was lower Mediterranean colony [0.11, 95% CI (0.09, 0.14)] when compared Atlantic [0.18, (0.15, 0.22)]. The Western Oscillation index (WeMOi) explained 57% temporal variability breeders. In comparison, 43% breeders winter St Helena (wHIX) El Nino-Southern (wENSO). Our results suggest that remain this basin for where they may face costs more favourable conditions. contrast, breeders’ be higher cost migration, upwelling Benguela current heavy storms over route during La Nina events. This study underlines importance modelling separately different causes testing effects climatic covariates.